Switch construction



March 17, 1942. N. c. SCHELLENGER 2,276,673

SWITCH CONSTRUCTION Filed April 27, 1939 INVENTOR,

ATTORNEY5 particularly small house Patented Mar. 17, 1942- UNITED STATES PATENT OFFICE Newton Q. Schellenger, El

Chicago Telephone Supply Paso, Tex., assignor to Company, Elkhart,

Ind., a corporation of Indiana, Application April 27, 1939, Serial No. 270,280

8 Claims. (01. 200-67) This invention relates to a new and improved switch, and more particularly to a switch especially adapted for association with a volume control for joint operation.

The requirements of present day radio sets, sets and automobile sets, necessitates the use of switches and volume controls that occupy a minimum amount of space.

It is important therefore that the switch assembly be of small size and that it also be capable of ready association with an equally small volume control to form a compact unit. To economize space, it is desirable to have the switch and volume control of the same diameter and in a small switch where the number of component parts has been reduced, it is important that the operating mechanism be protected from mechanical interference with adjacent parts.

With usual types of switches enclosed in a housing having metal side walls with depending ears for engagement with the top wall of a variable resistance housing, it is necessary to have the switch housing smaller than the variable resistance housing in order that the ears may pass through the top wall of the latter housing. Since switches are made in comparatively small sizes, this has presented no difiiculties with the usual variable resistance devices. The present tendency, however, is for the variable resistance to be the smallest possible size and the present invention provides means wherebythe switch may be readily mounted on a variable resistance of no greater diameter than that of the switch.

Devices of this character are made in large quantities and sold at low prices so that the cost of a unit must be kept to the minimum. Further, the devices are often subjected to hard usage. Consequently, it is important to keep down the number of parts required, both to keep down the cost and to simplify the structure to reduce possible structural failure under heavy and continued use.

In many uses of such devices the switch carries current which may transfer hum or undesirable disturbances to the associated variable resistance. For this reason it is desirable to ground the switch cam so that it cannot assist in such transfer, but on the contrary will serve, in part at least, to block the opening in the variable resistance housing through which it extends.

It is an object of the present invention to provide a new and improved switch construction.

It is a further object to provide a switch for association with a volume control to form a compact unit.

It is also an object to provide a switch having a new and improved pltman mounting which has the additional function of grounding the switch cam.

It is an additional object to provide improved means for jointly mounting a switch and a volume control unit.

It is another object to provide a switch which may be readily mounted in association with a volume control having the same diameter.

It is a further object to provide novel means for limiting the movement of the switch arm.

Other and further objects will appear as the description procee I have shown certain preferred embodiments of my invention in the accompanying drawing, in which- Figure 1 is a of the spring contacts Figure 2 is a view similar to Figure 1 but showing the actuating cam and switch arm at their counterclockwise limit of movement;

Figure 3 is a view of Figure 1 as seen from below; and v Figure 4 is a vertical section taken through the switch on line 4-4 of Figure 1.

The switch comprises a base I which, in the form shown, is a flat disc having a locating notch H formed in its periphery to receive an indentation 4| in the housing 39. This base will normally be formed of non-conducting materials,

such as sheet fibre, Bakelite or other synthetic pivot post l2 passes and the pivot post is the cover. The enlarged shoulder or flange I 4 also serves as a seat for the switch arm 15. The shoulder I4 is of a thickness equivalent to the height of the exposed ends of the portions 23 of various parts are held in place by the enlarged head IQ of the pivot l2, which is formed after the parts are assembled on the pivot.

The switch arm having rounded contact faces 26 surrounded by shoulders 2| which secure them to the arm.

The switch arm 15 is preferably formed of sheet material similar to that of which the base III is formed, and has non-conducting raised portions 22 which engage the spring contact the contact springs 24 when the arm I5 is in "ofi position, thereby preventing looseness of the .arm in that position.

The spring contacts'24 include end portions which are held to the base Ill-by rivets 25, and connecting or soldering lugs 26 which extend to the outer face of the base through slots, as shown in Figure 3. I p

The fixed contact members 21 and their contact portions 28 fit into perforations 29 formed in the base member ID. These contact portions are substantially in the plane of the inner face of the base member Hi. The outer portions of the contact member 21 are secured to the outer.

face of the base member I by means of rivets 30. The contacts 21 are also preferably formed with integral connecting lugs 3|.

The actuating cam comprises a lower portion l8 and upper portion 32 which have separate bearings on the pivot l2. These portions I8 and 32 are preferably integrally connected by the lateral portion 33. The lower portion [8 is provided with a downwardly extending lug 34 which fits in a notch or opening 35 formed in the end of the switch arm I opposite to that on which the contact rivets iii are carried. The opening 35 is materially greater in size than the lug 34 so that the switch arm is movedwith a quick, snap action when the parts pass the dead center position. g

The portion l8 of the cam also carries the upwardly extending T-head 36, upon which is fitted the slotted end 31 of the pitman 38. The op.- posite end of the pitman 38 passes through a perforation 39' formed in the bottom of an indentation 40' in the side wall ofthe tubular housing 38.

Two other similar indentations 40" are also formed'in the side wall 39 at points so located that the three indentations are substantially equi-spaced about the circumference of the housing. All of these indentations extend from the open edge of the side wall 39 to the inner face of the base where they form shoulders 42' which clamp the base down onto the flange 40.

At their innermost portions, or the bottoms of the pockets formed thereby, the indentations have attaching ears or tongues 42 projecting therefrom. These ears 42 provide for the attachment of the switch to a volume control no larger in diameter than the switch.

The coil spring 43 is carried by the pitman 38; one end engages the shoulder of the slotted end 31 of the pitman, and the opposite end engages the bottom wall of the pocket 48 at the inside of the housing 39 adjacent the aperture 39' through which the end of the pitman 38 passes. It will be noted that the pocket 40 is deep enough so that when the cam is in a dead center position, the end of the pitman does not extend beyond the normal outline of the housing 39, and consequently the operation of theswitch is protected from mechanical interference by adjacent IS in the form shown carries .a pair of con act members 16 comprising rivets spring 43 with the wall serves to ground the actuating cam.

It will be notcdthat the slot 48 in the end of the pitman 31 is sufficiently large to easily pass over the T-head 36. To facilitate the assembly operation the slot 48 is set at an angle substantially corresponding to that of the T-head when it is at either its limit of clockwise or counterclockwise movement. By using a pitman which is longer than the spring 43 when not compressed, the spring may be slipped over the pitman and the end'of the pitman38 passed through the perforation 39'. The protruding end 38 may be grasped and the spring 43 compressed to a point where the slot in the end of the pitman 31 may he slipped over the T-head 36. The excess length of the pitman extending through the side wall, represented in dotted lines in Figure 2, may then be. broken off. In order to facilitate the break and insure it occurring at the proper point, the pitman is notched at the desired finished length. This construction makes it possible to assemble the pitman and spring in the last operation after the other parts of the switch have been assembled.

The switch arm 15 is provided with oppositely projecting portions 44, one of which abuts the side wall of the housing 39 when the switch arm is in the "on position, as shown in Figure l, and the other abuts the side wall when the switch arm is in the off" position, as shown in Figure 2. These projections serve as stops, and having a relatively small contact area with the side wall,

there'is a very little starting friction when the The switch may be readily mounted upon a volparts. The engagement of the pitman 38 and me control unit by inserting the ears 42 in slots in the end wall of the housing for the volume control unit and bending them over. Where the volume control unit is of the same diameter as the switch the inset ears are inside of the plane of the side walls of both units'and the slots in the volume control are set inwardly from the side wall. As shown in Figure 4, the side wall of the volume control housing is indicated at 45 and the end wall portion at 46; the ear 42 extending through a slot in the end wall is shown bent over in clamping engagement with the under face of this wall.

This feature of locating the attaching ears in from the periphery of the casing to enable the switch to be mounted on a control unit no larger in diameter than itself is covered in a divisional application, Serial No. 372,085, filed December 28, 1940.

While I have shown certain preferred embodiments of my invention, these are to be understood to be illustrative only as it is capable of variation to meet different conditions and requirements and I contemplate such modifications as come within the spirit and scope of the appended claims.

I claim:

I. A switch comprising: a substantially circular fiat base a substantially cylindrical metal side wall extending up from the periphery of the base to 'coact therewith in the formation of a subenclosure formed thereby;

2,276,673 stantially cup-shaped enclosure, said side wall having an integral portion thereof indented a. I

substantial distance into the enclosure directly over the adjacent face of the base with the bottom of said indentation having an opening pro-' nalled in the bearing provided by the opening in said indented portion of the side wall so as to be constrained to motion between definedlimits in a plane substantially normal to the axis of the enclosure, the radial distance of said bearing for the pitman from the axis of the enclosure being so related to the length of the pitman and its extent of motion that the extremity of the slidably journalled end of the pitman is at all times maintained between the cylindrical periphery of the side wall and the bearing for the pitman.

2. A switch of the type to be mounted on the 'back of a small radio control instrumentality of the rheostat type comprising: an insulating base; a metal side wall encircling the base and having anintegral instruck portion overlying the base to provide a pocket opening to the outside the bottomof which is apertured to provide a bearing located a substantial distance inwardly of the adjacent portions of said side Wall; a toggle type snap switch mounted on the base inside the side wall and including a movable switch arm constrained to motion across the inner face of the base; a toggle spring for the switch; and a spring guiding pitman having one end operatively connected with the movable switch arm and its other end slidably journalled in the hearing at the bottom of said pocket, the toggle spring being mounted on the pitman and said pitman being of such length that in its position of maximum projection the projecting outer end portion is substantially no longer than the depth of the pocket.

3. A switch of the type adapted to be mounted on the back of a small radio control instrumentality of the rheostat type comprising: a substantially cylindrical metal side wall having an integral instruck portion providing a pocket opening to the outside, the bottom of said pocket having a hole therethrough to provide a bearing spaced inwardly from the cylindrical periphery of the side wall; an insulating base closing one end of the side wall and coacting therewith to form a substantially cup-shaped enclosure; a toggle type snap switch mounted on the base inside said enclosure and including a pivot fixed to the base about which the movable elements of the switch oscillate; a spring guiding pitman having one end connected to one of the movable members of the switch and its other end slidably journalled in the bearing at the bottom of the pocket formed by said instruck portion; and a coil spring on said pitman confined between the inner face of the instruck portion and a shoulder near the connection of the pitman to said movable switch member for yieldingly holding the movable switch parts in either of two predetermined positions, the pitman moving out through the bearing in the bottom of the pocket as its connection to said movable switch member crosses dead center, and said pitman being of such length and the pocket substantially no having such depth that in mum projection, the end portion of the pitman projecting through the bottom of the pocket is longer than the depth of the pocket.

4. In a switch of the character described: an enclosure including a base and a side wall extending up from the base, said side Well being indented a substantial distance into the enclosure to provide a pocket opening tothe outside with the bottom wall of the pocket integral with said side wall and having a hole therethrough facing the opposite side of the enclosure; a toggle yieldingly holding. the actuating cam and consequently the switch arm at either of its positions; a spring guiding pitman; and aconnection between one end of the pitman and the actuating cam, said connection being detachable in a predetermined relative position of the pitman and actuating earn, the opposite end of the pitman being slidably projected through the hole in the bottom wall of the pocket, whereby said pitman may be grasped exteriorly of the switch enclosure to facilitate its attachment to the actuating cam; and said extending end portion of the pitman being readily severable after assembly of the parts, at a point such that the remaining projecting end portion of the pitman when in its maximum position of pro ection is substantially no longer'than the depth of the pocket.

v5. In a switch of the character described: an

enclosure including a base and a side wall extend ing up'from the base, said side wall being indented a substantial distance into the enclosure to provide a pocket the bottom wall of the pocket integralwith said tion being detachable in a predetermined relative position of the pitman and actuating cam, the opposite end of the pitman being slidably probe readily broken oif, said means being so located that the remaining projecting portion is substantially no longer than the depth of the pocket when the pitman is on dead center.

6. In a switch of the character described: a housing including a substantially cylindrical side spring for yieldingly holding the actuating cam and consequently the switch arm in either of its positions; a spring guiding pitman having one end slidably supported by said cylindrical side wall of the housing; and means detachably connecting the opposite end of the pitman with said actuating cam, said means comprising an undercut lug and its position of maxia slot, the major axes of which are inclined to the longitudinal axis oi the pitman'so that assembly of said pitman and actuating cam necessitates lateral displacement of one of said parts with relation to the other irom the normal position of said parts maintained by the toggle spring.

7. In a switch of the character described: a housing including a substantially cylindrical side wall and a base adjacent to one end of the side wall; a switch arm pivoted on the base and adapted to be swung from one position to another; an actuating cam for the switch arm; a substantially T-shaped lug projecting laterally from the actuating cam; a toggle spring for yieldingly holding the actuating cam and consequently the switch arm in either of its positions; and a spring guiding pitman slidably supported at one end by said cylindrical side wall of the housing and having an elongated slot in its opposite end engaging said T-shaped lug, said slot having its major axis disposed at an angle to the longitudinal axis of the pitman so that connection of the pitman and actuating cam necessitates lateral displacement of the pitman from its normal position to which it is urged by the spring when the pitman is connected to the actuating cam.

' 8. Ina snap switch: a housing having a metal side wall adapted to be electrically grounded; an insulated base; toggle type switch mechanism mounted on the base including a pivoted switch arm and a pivoted actuating cam drivingly connected with the switch arm; a spring guiding pitman having one end slidably received in a hole in the metal side wall and the other end connected to the actuating cam by means of an undercut lug and slot; a shoulder on the pitman adjacent to said connection; and a toggle spring on the pitman bearing against said shoulder and the side wall so that said spring maintains said connection with one edge of the slot bearing securely against the lug to thus electrically ground the actuating cam to the housing side wall in addition to yieldingly thrusting the actuating cam and consequently the switch arm to one or the other of its two positions.

NEWTON C. SCHELLENGER. 

